<html>
<pre class="textdiagram" id="fig8">
        +---+          |  +---+
+---+   |   |   +---+  |  |   |
|   +-->|   |   |   |  |  |   |
|   |   +---+   |   |  |  +-+-+
+-+-+           +-+-+  |    |
  |               |    |    |
  |       +-----------------+
  |       |       |    |
  +-----------------------+
          |       |    |  |
  +-------|-------|----+--|------+
  |       v       |       v      |
+-+-+   +---+     |     +---+    |
|   |   |   |   +-+-+   |   |    |
|   |   |   |   |   |   |   |    |
+---+   +---+   |   |   +---+    |
          ^     +---+     ^      |
          |       ^       |    +-+
  +-------+-------+-------+    |
  |       |       |            |
  v     +-+-+     v     +---+  |
+---+   |   |   +---+   |   |  |
|   |   |   |<--+   |   |   |<-+
|   |   +---+   |   |   +-+-+
+---+           +---+
</pre>
</html>
